Mallory body was produced in griseofulvin fed mice, which was investigate transmission and scanning electron microscope, immunoflourescenece, and immunoelctron microscope. Antibodies used in this studies were anti mouse cytokeratin antibodies (CK 55 and CK 44), anti hunlan cytokeratin antibodies (AE 3 and EAB 903) and polyclonal anti ubiquiti. n (Ub) antibody.Disorganization of intermediate filaments (IFs) was noted in the cytoplasm of hepatocytes with Mallory body formation, however, IF network was noted in the hepatocytes with Mallory body. MBs were stained with anti CK55 antibody, however, some of the IFs in hepatocytes with 1-IB were not stained with-anti CK 55 antibody.AE3 and EAB90-3 were positive for iABs but negative for IFs. . lBs were stained with both CK55 and Ub. imnlunoelectron microscope confirmed the existence of IFs in the cytoplasm of hepatocytes containing MBs without staining by anti CK55 antibody.Our results indicate that phenotypic change of MFs occurred in the process of MB formation and Ub might play an important role in the degradation of MBs. The abnormal protein metabolism through UB may be one of the factor of MB formation.